Vascular prostheses on the basis of synthetic fibres manufactured by means off textile technology have already been known. They differ from each other by their construction, the materials used and eventually also by the manufacturing technology. The goal of these different approaches according to the prior art is to improve the short- and long-term patency of the reconstruction, to improve the surgical characteristics, and to overcome some negative effects, such as for example provocation of infections. There have already been known combined vascular prostheses comprising non-resorbable materials, for example synthetic fibres, and resorbable materials, for example catgut, gelatine, collagen, albumin, etc. These resorbable materials are usually introduced by means of impregnation.
CS-A-116 540 relates to highly porous collagen-fabric vascular prostheses and a method for the manufacturing thereof. In these prior art prostheses, a combination of a self-supporting tube made from collagen with a knitted frame made from synthetic fibres serving for a substantial increase of the porosity of the fabric is used. A similar solution has been known from CH-A-645 532 which describes a vascular prosthesis of tubular form, where an internal layer, which is porous and made from a resorbable material, is provided on the internal surface of an external layer manufactered from a non-resorbable material. A fundamentally opposite construction of a vascular prosthesis has been known from FR-A-2 541 888. The principal disadvantages of both these solutions on the basis of a two-layer structure in comparison with the present invention, which is based on a three-layer structure, are the not completely secured attachement of the layers and the not exactly defined resorbability of the resorbable layer.
EP-A-47 231 relates to a three-layer vascular prosthesis. However, all the three layers of this prosthesis are made from a non-resorbable material, the external layer comprises interstices produced by means of a laser beam, and the middle layer is a knitted fabric. The principal disadvantages of this construction are the non-resorbability of all layers and the high costs of the laser processing of the external layer.
It is the object of the present invention to overcome the problems of the prior art prostheses and to provide vascular prostheses and methods for the manufacturing thereof which effectively prevent leaking around the sutures and simultaneously positively influence the character of the newly formed tissue surrounding the vascular prosthesis. In addition thereto, their structure should guarantee the temporary attachment of all layers together during the time needed for the surgical implantation. Furthermore, the vascular prostheses should be obtainable by a simple and low cost process.